[Engine-devel] Feedback on ovirt-engine-sdk

[Yaniv Kaul]

On 11/27/2011 11:16 AM, Michael Pasternak wrote:
> Hi Geert,
>
> On 11/26/2011 07:49 PM, Geert Jansen wrote:
>> Hi Michael,
>>
>> i just wrote a small program with the new Python SDK. I found it very easy to use, so great work. I do have a few points of feedback:
>>
>>   * Probably we want all Exceptions derived from a single base class. That way, the user can intercept any ovirtsdk with a single try/except clause. Currently that's not
>> possible, as all your exceptions derive directly from Exception.
> sure, in my TODO list.

Would be great if you could publish the TODO list on the ovirt Wiki.
It would encourage others to work on those items as well.
Y.

>
>>   * I think the .get() method should be id-based not name based. Using "id" as a primary key has a number of advantages over name:
>>
>>    - It is immutable, which makes e.g. renaming a lot easier.
>>    - It allows you to retrieve an object without a search query or a filter.
>>    - It matches how the API works as well.
> "id" is supported, you can do api.collection.get(id=xxx), only as you mentioned
> "id" is not primary, but secondary key (i thought that searching by name will be easier),
> but i can change it in a second if this is an issue.
>
>>    Also currently i think it's not possible to retrieve a resource by its ID, unless you use the id= keyword argument to list() which retrieves the whole collection and then
>> filters out the matching id.
> nope, it's supported - i even added it to examples.py [1]
> ->  vm5 = api.vms.get(id='02f0f4a4-9738-4731-83c4-293f3f734782')
>
> [1] will add it to get method .get(id, name) as you suggested.
>
>>   * You may want to introduce some non-entity related operations, like ping(), and connect(). These allow you to better control when you connect, and allow an program to
>> test if the connection details work. That helps client except the right exceptions at the right time, and display more relevant error messages.
> - no need for explicit connect() as its done implicitly on proxy construction
> - no need for ping() as any attempt to use disconnected (and not recoverable) proxy, will cause ConnectionError,
>    so user should only /Trap/ this exception for disaster_recovery
>
>>   * There's two Python objects involved for each API object. For a VM for example, you have params.VM and brokers.VM. This distinction is made visible to the user, for example:
>>
>>    template = api.templates.get('Blank')
>>
>>    vm = params.VM()
>>    vm.name = 'foo'
>>    vm.template = template  # ERROR
> yep, you right doing this is in my TODO list as well
> (had to switch to CLI, so i do have few leftovers[1] - this is one of them)
>
> [1] they all have simple workarounds (like this one as described below)
>
>> The last line need to be:
>>
>>    vm.template = params.Template(id=template.id)
> for now (as workaround you can pass 'superclass', e.g vm.template = template.superclass),
> but i suggest you just wait for another day till I'll support this.
>
>> In my version of the Python API i used mix-in classes to add the OO behavior to the generated classes. It was easy, because PyXB had support for that. This gave me the
>> single class behavior. I am not sure if GenerateDS generated code allows that. I'm pretty sure it could be done though, but you may need to do some Python magic.
> no need, i do this with regular inheritance pattern
>
>>   * Nitpick: should this just be called "ovirt" instead of "ovirtsdk"?
> initially it was, but since both cli&  sdk would operate in same namespace,
> i wanted to avoid future collisions and renamed them to ovirtsdk/ovirtcli.
>
>> Overall great work though!
> 10nx a lot mate.
>
>> Regards,
>> Geert
>> _______________________________________________
>> Engine-devel mailing list
>> Engine-devel at ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/engine-devel
>